Structures and electronic properties of Si nanowires grown along the [1 1 0] direction: Role of surface reconstruction

The atomic and electronic structures of silicon nanowires grown along the [1 1 0] direction are systematically investigated using first-principles pseudopotential method. For nanowires whose diameters are ∼4 nm, the calculations taking account of various surface reconstructions both with and without hydrogen atoms on nanowire facets demonstrate that the reconstruction on nanowire facets is strongly dependent on hydrogen chemical potential μH. The nanowire terminated by H atoms is stabilized for high μH whereas the pristine nanowire is favorable for low μH. The nanowires with partially hydrogenated facets also appear within a certain μH range. Peculiar features in the electronic structure caused by facet edges are found in both pristine and partially hydrogenated nanowires.